Carbureting process



Original Filed July 31, 1929 5 Sheets-Sheet 1 v. &l I

INVENTOR- BY M M ATTORNEY May 8, 1934.

E. DICKEY I CARBURETING PROCESS Original Filed July 31, 1929 5 Sheets-Sheet 5 gi 22 2202? W E a Q 0 INVE TOR ATTORNEY Ma 8, 1934. E DICKEY 1,958,381

CARBURETING PROCESS Original Filed July 51, .1929 5 Sheets-Sheet 4 m 5 o u,

Q 5 O r; E f

[ I INVEgVTOR ATTORNEY May 8, 1934. I E. DICKEY 1,958,381

CARBURETING PROCESS Original Filed July 51, 1929 5 Sheets-Sheet 5 INVETOR z f jlw wwag ATTORNEY Patented May 8, 1934 CARBURETING PROCESS Ernest Dickey, Dayton, Ohio, assignor to Delco- Light Company, Dayton, Ohio, a corporation of Delaware Original application July 31, 1929, Serial No.

382,445. Divided and this 29, 1930, Serial No. 424,308

application January 2 Claims. (01. 48-219) This invention relates to a method of supplying gas suitable for household use.

This invention is a division of my copending application for Electrical apparatus, Serial No. 382,445, filed July 31, 1929.

An object of this invention is to provide an improved method of carbureting air which provides carbureted air of substantially constant richness.

Further objects and advantages of the present invention will be apparent from the follow ing description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a side elevation of a carburetor embodying features of this invention;

Fig. 2 is a diagram showing characteristics of certain hydro-carbon substances;

Fig: 3 is an enlarged view in cross section of a portion of the. apparatus shown in Fig. 1;

Fig. 4 is a top plan view of a portion of th apparatus shown in Fig. 1; Fig. 5 is an elevational view taken from the rear of Fig. 3;

Fig. 6 is a view in cross section of a pressure equalizing and bypass valve embodying features of the present invention;

Fig. 7 is a diagrammatic view of a portion of the apparatus which may be used for practicing the method.

Heretofore it has been the practice to supply gas, suitable for household use by contacting air with gasoline in order to form a mixture rich enough to burn in gas stoves, water heaters and the like. However, this practice has been attended with difficulties for the reason that the quality of the gas obtained by this practice has not been of a uniform quality. When the gasoline is fresh, that is, when only a small quantity of air has been contacted therewith, the carbureted air is rich for the reason that highly volatile constituents are readily taken up by the air. However, when the charge of gasoline in the appliance has been used for some time, the carbureted air coming therefrom is very much depleted in its gasoline content, for the reason that the gasoline in the carburetor has had the major part of its more readily volatile constituents taken up in the first stages of carburetion. According to this invention these and other difficulties are obviated.

A method according to this invention may include the rectification of a mixture containing hydro-carbons, such as gasoline, preferably casing head gasoline, in order to obtain a cut, or fraction, having all of its components of a character which may be readily taken up by air passing therethrough and of such character that when a charge or batch thereof has a stream of air passed therethrough at a substantially constant temperature, said charge will be taken up by the air with sufficient uniformity to maintain even combustion in the usual household burner. This out has all of its components so that 90% of said cut boils at atmospheric pressure below 100* F. and above 80 F. Preferably this cut or fraction has as its main portion one or more components, such as isopentane and/or pentane, boiling substantially at either 8'7.8 F. or 985 F. respectively, and its other minor components, if any, of such a character that 90% of the cut or fraction boils below 100 F. and above 80 F. This provides a fraction which may be handled with safety in closed steel drums, and which may be exposed in these drums to the ordinary air temperature conditions prevailing in practically all parts of this country. This is particularly true, since all of the components form a fraction which boils above 80 F., so that none of the components inthe mixture tends to build up great pressure within the drum when subjected to the highest temperatures prevailing in practically all parts of this country. On the other hand, all of the components in the fraction or out are readily taken up by air contacted with this fraction or cut at temperatures prevailing in practically all parts of this country and particularly under the conditions herein described.

The method also comprises contacting this cut or fraction with air to supply gas suitable for household use. A preferred manner. of contact- .ing the air with the fraction or cut is by passing air,preferably in the form of a stream in contact with at least a portion of said fraction. In 95 the preferred form, a charge or batch of the fraction or cut is placed in a container and air is contacted with at least a portion of said charge or batch,'at a substantially constant pressure, for instance, a pressure between constant pressurelimit's. 'When part or all of the charge or batch? has been taken up by the air, the charge or batch" may be periodically replenished by adding another charge of the same or similar fraction and continuing the contact operation.

' Because of the character of the cut or fraction the air takes up the hydro-carbon constituents from a charge or batch" thereof, if temperature conditions do not vary too much, at a substantially uniform rate and produces a gas of sufficiently constant richness so that ordinary burners in the appliances in which the gas is used do not have to be regulated from time to time during the complete consumption of said charge or batch in the manner heretofore necessary. This constant richness may be obtained as long as the temperature variations are such as occur during any one season of the year. The method may be practiced in any suitable manner and may be specifically practiced as disclosed herein. A mixture containing hydrocarbons, for instance gasoline, and preferably casing head gasoline may be supplied to a rectifying column 20. This mix ture may be introduced into the rectifying column 20 through a suitable inlet 21. vThe mixture may be subjected to a heating action by heat derived from the steam coil 22 at the bottom of the column and to a condensing action by means of the cooling coil 23 near the top-of the column. Thus a suitable reflux is produced in the column and a gas is discharged through outlet 24 in which there are no appreciable constituents boiling above 100 F. The. rectifying column may be of any suitable construction and, for instance, may be provided with perforated plates 25 of the usual construction having reflux return pipes 26 of the well-known construction. It may be provided with the usual boiling kettle 2'7 and the usual condenser 28. If casing head gasoline is introduced through the inlet 21, a superior automobile motor fluid may be withdrawn from the kettle 27, for instance, through the outlet 29. In view of the fact that casing head gasoline is obtained by condensing or absorbing some of the constituents of gas discharged from the casing head of a gas well, all of the constituents of casing head gasoline are relatively volatile, so that the motor fuel discharged through the outlet 29 is of a very high quality, and is free from, lighter constituents of easing head gasoline, which are undesirable in an automobile motor fuel for the reason that they volatilize in an undesirable manner when used in the automobile.

The mixture discharged through the outlet 24 of the rectifying column 20 may be introduced into another rectifying column 30, of similar construction to the column 20. The mixture after passing into the column 20 may be subjected to a heating action by means of the heat derived from the steam coil 32 and may be subjected to a condensing action by means of the cooling coil 33 at the top of the column, and the gaseous mixture remaining may be discharged through the outlet 34. The column 30 may be provided with the usual perforated plates 35, the reflux return pipes 36 and the usual boiling kettle 3'7. The column may also include the condenser 38. The kettle 37 may be provided with an outlet 39. If the mixture originally introduced in the inlet 21 is of a favorable type, the cut or fraction of the type heretofore described may be withdrawn through the outlet 39. However, it is to be understood that further rectifying steps may be necessary, as by providing other rectifying columns or by subjecting fractions obtained from one or more rectifying columns to a second rectifying process within the same one or more rectifying columns. By

proper rectification, well-known in the art, a cut' or fraction, of the character heretofore described, may be obtained either at such an outlet as indicated at 39, or possibly at some othenoutlet, for' instance near one of the perforated plates 35.

Some of the characteristics of the cut or fraction herein described are shown in Fig. 2. These characteristics are compared with the characteristics of other fractions or fuels. Fig. 2 is a chart which shown on the horizontal scale the percent of the fraction or cut distilled at atmospheric pressures. The vertical scale on the left shows the temperature, in degrees Fahrenheit, at which the fraction is distilled at atmospheric pressure. The vertical scale on the right shows the temperature at which the fraction or cut is distilled at atmospheric pressure in degrees centigrade. The distillation curve of the preferred fraction or out is indicated by the line A. Thus it is to be seen that at the begin- .ning of the distillation the fraction distills at approximately 8'7 Fahrenheit and that when of the fraction has been distilled the temperature is but Fahrenheit. The distillation curve is thus shown as a substantially flat hori zontal curve throughout 90% of the distillation. The 90% point of distillation may be taken as a convenient terminal point of the distillation curve, since hydrocarbon fractions generally begin to curve sharply beyond the 90% point. A fraction or out having a distillation curve which is as substantially horizontal as the one indicated at A may be carbureted by placing a charge or batch of the fraction or cut in a tank, and by contacting a stream of air with the entire batch or a portion thereof so that substantially all of the charge or batch is taken up by the air, if carburation is continued to that extent. Throughout the range of carburation of the charge or batch, the carbureted air takes gas stoves of the type generally used with this,

type of apparatus and an even combustion is maintained at the burner without the necessity of adjusting the air mixing valves of the burner.

When air is contacted with a batch of this type of saturated hydrocarbon an air gas mixture above the higher explosive limit is formed thereby eliminating danger of explosion and flash back.

For the ordinary temperatures prevailing in most parts of this country (United States of America) a fraction or out having the characteristics of curve A has been found to be satisfactory. However, in warmer portions it might be convenient to provide a fraction or cut having a curve substantially parallel with the curve A, but higher up in the temperature scale. Thus such a fraction might be indicated by the distillation curve B. In colder locations, a cut or fraction might be provided with a curve substantially parallel to the curve A but lower down in the temperature scale. Thus a fraction might be provided having characteristics indicated by the curve C. In general, it may be stated that such a fraction may be determined by its ability to be carbureted in the manner herein set forth to substantial dryness and to maintain an even combustion in the type of burner herein described without the necessity of adjusting the air mixing valves of the burner. Fractions or cuts having a distillation curve slightly less horizontal than curve A obviously may come within the spirit of this invention. Thus it maybe stated that a fraction or cut having all of its components so that 90% of the fraction or cut distills within a range of 50 Fahrenheit may be suitable for the purpose herein stated. Also preflie within a zone so that the initial boiling point is above 50' Fahrenheit and the 90% distillation point may lie below the 200 Fahrenheit. The preferred fraction or out herein described has all of its components so that the fraction or cut boils to substantial dryness at atmospheric pressure below 100 Fahrenheit and above 80 Fahrenheit, it being understood that above 90% distillation may be excepted. Also and more specifically, the preferred cut or fraction has as its main portion one or more components boiling substantially at either 8718 Fahrenheit or 985 Fahrenheit or both; and if it has any minor components, it has no other such minor components causing 90% of said fraction or cut to boil above 100 Fahrenheit and below 80 Fahrenheit.

Unless otherwise stated herein, it is to be understood that in the specification and claims of this application, the pressures at which the distillation or the boiling is to take place is the normal atmospheric pressure as usually understood in this art. Hydrocarbon mixtures, such as casing head gasoline, commercial gasolines, aviation gasolines and the like are indicated by the curves D, E, F and G. These mixtures have been found to be unsatisfactory in the type of apparatus herein described for the reason that with burners ordinarilyavailable it is necessary to adjust the air mixing valves of the burners supplied with carbureted air during the carburetion of substantially all of the charges or "batches of said mixtures even when the temperature is substantially constant. This adjustment is necessary because of the large variation of vapor pressure during the carburation of such a charge or batch. Curve H shows the characteristics of another cut or fraction containing largely hexane and/or its isomers which, under most favorable conditions, may be carbureted without the adjustment of the burners as herein disclosed.

When this invention is to be practiced in localities where the temperatures vary a substantial amount as between seasons of the year etc., it may be desirable to provide a compensating factor for the variation in the richness of the carbureted air which follows the change in vapor tension caused by the such changes in seasonal temperatures. When a relatively large body of the fuel, embodying this invention, is stored under ground and there contacted with the air to be carbureted, changes in temperature of short duration, such as caused by atmospheric storms passing over the country, do not-disturb, to a substantial extent, the richness of air saturated with vapors from said body of fuel. However, the gradual change in ground temperature due to seasonal changes may disturb the richness of the carbureted air sufficiently to necessitate a seasional adjustment of the ordinary household gas burner. In order to obviate even this seasonal adjustment a compensating factor may be introduced. Thus the carbureted air may be diluted with air in accordance with the ground or fuel temperature so that a mixture of carbureted air and diluting air is obtained which provides a gas of substantially constant hydrocarbon content or calorific value regardless of the temperature of contact between the air and fuel. In one form,

the carbureting device may be adjusted to pro-- vide carbureted air saturated with hydrocarbon at the lowest temperature encountered, and the dilution with air may then be made so that at higher contact temperatures an unsaturated carbureted air is provided which carries the same hydrocarbon content as the said carbureted air saturated at the lowest temperature in a manner hereinafter more fully described.

However, in most climates it will be found that when the carbureting chamber is properly located a sufficient depth under the ground that the compensating mechanism referred to in the previous paragraph. is not necessary. It is ordinarily necessary only in climates where there is a rather wide difference in seasonal temperature.

The cut or fraction obtained as previously described may be contacted with air in a suitable apparatus. For instance, in an apparatus or system of the type shown in Fig. 1 designated 40. The cut or fraction may be contacted with air in the form of a stream of air, at a substantially constant pressure. This substantially constant pressure may be a pressure between constant pressure limits. Thus a charge, or batch of the cut or fraction may be introduced into a tank 42, through a feed pipe 44. Air in the form of a stream may be contacted with at least a portion, or preferably all of the charge or batch within the tank 42. duced by means of a perforated pipe 46 placed near the bottom of the tank 42. The air, laden with the proper amount of hydrocarbons may be withdrawn through the pipe 48 and may have its pressure reduced, if necessary, by means of an automatic pressure reducing valve 49, which discharges the carbureted air at a substantially constant pressure through the pipe 50 leading to suitable appliances such as household gas stoves having the usual type of burners used with this type of apparatus, water heaters, small industrial gas burners or the like. For ordinary household use, the gas in the pipe 50 may be maintained at a substantially constant pressure of 4 oz. by means of the pressure reducer or regulator 49.

Air may be supplied to the pipe 46 at a substantially constant pressure by any suitable mechanism, such as, an air supplying device 55. It may comprise a compressor 56, drivingly connected by a belt 57 to an electric motor 58. The compressor 56 may have a connection with the pipe 46 which connection includes an air tank 60, an oil separator 61 and pipe connections 63 and 64. The oil separator 61 may, if desired, be connected to the compressor for feeding oil thereto. The compressor 56 may have its inlet 66 extended as shown at 67, for instance to the exterior of the building in which the device is located. Preferably the tank 42 may also be placed outside of the building, which is to be supplied with gas. Also if desired the tank 42 may be buried underground and may be provided with the liquid inlet 44 and a liquid level gauge receiver 70 leading to the top of the ground. Either the pipe 48 or the pipe 50 may be laid into the building which is to be supplied with gas. Thus by placing the tank 42 underground, the temperature of the fuel will not be varied to a substantial extent except during seasonal temperature variations.

Details of the device 55 may be of any suitable construction, and may be, for instance, similar to the type described in my Patent"#1,944,225 issued January 23, 1934. Thus the device 55 may include the rotary compressor 56 having rotating vanes 75. The compressor may discharge through a pipe 78 leading below the level of a body of lubricating oil 79 in the air tank 60. The separator may be provided with baflies 61a and with an outlet 62 connected to the pipe 78 leading below the level of the body of lubricating oil The stream of air may be pro- I '79 in the air tank 60. Thepipe 63 is connected to the air tank 60 above the level of the oil 79 and the other end connected to the pipe connection 64. Preferably a check valve 81 is provided which permits the air to flow into the tank 42 but prevents the return thereof. A suitable check valve 83 may be provided which permits an upward flow through the passage 85 but which falls into place and prevents a downward flow. Should there be a slight leakage in the check valve 83, the lubricating oil 79 would be forced up through the pipe 78 and outlet 62 and would form a liquid seal above the check valve 83. The liquid seal would be far more effective than a gas seal so that the slight air leak would be effectually stopped.

The compressor 56 may be operated so as to maintain a substantially constant pressure in the tank 60. Thus a pressure responsive switch 88 may be connected by means of pipe 89 with a connection 90 leading to the tank 60. The switch' may be responsive to pressures within the system or tank 60 and may be set so as to start and stop the motor 58 through the electrical conduit 92 in response to constant pressure limits with the tank 60. Preferably these limits are 2 pounds when the motor starts and an upper limit of 7 pounds when the motor stops. The pressure switch also includes an emergency limit or low pressure cut-out position so that if the pressure within the tank 60 falls below the low pressure limit, in this case 2 pounds, the switch will render the electrical driven compressor 56 inoperative, and in so doingwill assume a position whereby the compressor will not be rendered operative until a manual reset 100 is actuated to cause the switch to assume the normal low' operating pressure limit or closed circuit position. Thus, if for I any reason the source of electricity which is connected with the motor 58 should fail so that the pressure within the tank 60 falls below 2 pounds, the switch will assume the emergency or low pressure cut-out position to prevent the motor from starting again until after the reset 100 has been manually actuated. This would prevent the car- -buretor or system from supplying carbureted air to the apparatus after a failure of the source of electricity. This is advantageous for the reason that it would be dangerous to supply. carbureted air after such appliances may have become extinguished by reason of the failure of carbureted air supply. Further details of the pressure responsive switch 88 may be found in my copending application for Electrical apparatus, Serial No. 405,257, filed November 6, .1929.

Thus it is to be seen that the compressor 56 is intermittently operated. Means may be provided for lubricating the compressor during the period of operation. During the period of operation the space 105 in the separator 61 is substantially at the same pressure as tank 60, that is, it is super-atmospheric pressure. This superatmospheric pressure forces oil from the bottom of the separator 61 through a pipe 107 connected to a pipe 108 leading to an inlet 109 of compressor 56. The inlet 109 may be placed in a: neutralposition of the compressor 56, that is, half-way between the low pressure and high pressure sides thereofwhere the pressure is substantially atmospheric pressure. Thus during the running period of .the compressor, oil is fed thereto, due to the difference-of pressure in the separator and the inlet 109, but during the period of idleness of the compressor 56, the pressure in the space 105 drops substantially to atmospheric pressure because of air leakage in the compressor, and no oil is forced through the pipes 107 and 108 into the inlet 109. If desired, the separator may also be provided with an oil gauge 110 which may be connected to the threaded plug 111 engaged with the casing of the separator. This gauge or rod 110 may be removed in order to determine the oil level in the separator 61, by inspection of the oil covered portion of the rod 110.

In order to control the amount of oil flowing through the pipes 107 and 108 during the operation of the compressor 56, the pipe 107 is provided with a controlling valve or opening 115. When the space 105 of the separator 61 is at super-atmospheric pressure, a portion of the air in the space will escape through the opening 115 to thus decrease the amount of oil which would otherwise flow through the pipes 107 and 108. Thus the amount of oil to the compressor 56 depends upon the air flowing through the opening 115, which opening may'be varied in size to proportion the amount of oil and air to thus supply the proper amount of oil to the compressor 56. By the present arrangement, the pipes 107 and 108 may be of sufii cient size so as not to be readily clogged by any dirt particles which may collect in the body of the lubricant, thus insuring lubricant to the compressor during the operation thereof. Thus it is not necessary for the lubricant to flow through needle valves, minute orifices or the like in order to provide for the regulated flow of the lubricant. Furthermore, in order to permit the use of large lubricating pipes and regulatingpassages, the lubricant is directed to a rotating bearing like surface which may aid 110 in retarding the flow of lubricant. In this particular embodiment the inlet 109 is directed to the bearing like surface between the rotating cylinder 75a and the upper part of the wall of the cavity-56a.

As a safety precautiomin the event of a leaky check valve 81 and a leaky connection between the tanks 42 and 60, there is provided a pressure equalizing valve 125 which is shown in detail in Fig. 6. The valve 125 interconnects the pipe 120 connections 63 and 64 and has a pipe connection 127 with the gas space 130 of the tank 42. Thus in the event a leaky connection should develop between the tanks 42 and 60, the pressure in the air tank 60 would diminish to thus decrease the pressure in the pipes 63 and 64, and in so doing the pressure in the gas space 130 of the tank 42 will force the check valve 126 of the valve 125 from its seat 132 to thus relieve the pressure in the gas space of tank 42 and thereby equalize the pressure within the gas space and pipes 63 and 64. Thus the pressure in the gas space will not force liquid fuel through the leaky check valve 81, in the event said valve should be leaky, to thus force liquid fuel from the tank 42 through the leaky 135 connection which may develop between the tanks 42 and 60.

Sometimes the apparatus may be subjected to. extreme and unusual variations of temperature, or may not. be buried to a sufficient depth under ground. Under such circumstances it has been found desirable to dilute the saturated gas in the gas space 130 in the tank 42 with a predetermined amount of air in accordance with seasonal temperatures in order to vary the richness of the gas supplied to the pipe 50 to thus supply gas of a substantially constant richness, hydrocarbon content or calorific value. During relatively cold weather it may be desirable to supply a mixture of rich gas to the pipe 50. However, this rich I56 saturated gas may be diluted with air during warmer weather when unsaturated gas of a predetermined mixture will be of a richness or calorific value equal to saturated gas in colder weather. In order to dilute the saturated gas in the space 130 of tank 42 there is provided as a compensating factor, preferably, a diluting or by-pass valve 135. For the purpose of convenience the valve 135 has been secured to the casing 137 of the pressure equalizing valve and is adapted to by-pass a predetermined amount of air from the pipe 63 to the pipe 127 leading to the gas space 130. The valve 135 may be controlled manually or may be controlled in response to the temperature of the fuel-in the tank 42. A handle 139 has been provided for actuating the valve 135 manually and may be actuated to allow a greater amount of air to pass into the gas space 130 in warm weather and to decrease or entirely prevent the flow of air to the gas space 130 during cold weather. When it is desired to control the valve 135 automatically there may be added a thermostatic bulb 140 which may be disposed within the fuel tank 42 and may have a pipe connection 141 leading to an expansible bellows 143 which may be, for instance, if desired, connected to the by-pass valve 135 for automatically controlling the amount of air passing to the gas space 130 in response to the temperature of the fuel in the tank 42. Under such conditions the manual operation of the handle 139 would be unnecessary. Thus it will be noted that the gas supplied to the pipe 50 will be of a substantially constant richness at all times.

If the tank 42 is located a sufficient depth under ground and where the range in average seasonal temperature is not great it will be found that the apparatus may be simplified by omitting the diluting mechanism described in the previous paragraph since the variation in the richness of the mixture will not be sufficiently great to make such a mechanism necessary. However, where the mechanism described in the previous paragraph is used with my invention the device may be successfully employed in almost any climate regardless of the fluctuation in temperature.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms limit, said body of fuel being such that 90% thereof boils below 175 F. and within a range of 50 F., bubbling through said body of fuel a stream of air to form an air-gas mixture above the higher explosive limit, storing under superatmospheric pressure the air-gas mixture thus formed, and conveying the mixture to the point of use.

2. The method which comprises maintaining in an environment substantially unaffected by rapid variations in atmospheric conditions, a large body of a saturated hydrocarbon fuel having a vapor pressure under all normal atmospheric conditions sufficient to permit the formation of an air-gas mixture above the higher explosive limit, said body of fuel being such that 90% thereof boils between 80 F. and 100 F., bubbling through said body of fuel a stream of air to form an air-gas mixture above the higher explosive limit, storing under super-atmospheric pressure the air-gas mixture thus formed and conveying the mixture to the point of use.

' ERNEST DICKEY. 

